I have a Trane heat pump unit (3 ton) that the electronic txv shuts down to the point it causes the coil to ice up. It was installed 3 months ago and worked fine until 2 days ago. The board is indicating low super heat or a stuck valve. I can cycle the power and it runs great for a day and then stops cooling yet the compressor sitll runs at 50 suction and 300 head. The system is 410. Any suggestions? All pressures are good during normal operation.

08-20-2012, 07:45 AM

heresjohnnyb

I need more info. These txv's will compensate on an inadequate charge in the system. That leads me to believe that it is short on 410. You may have a leak. Be sure to check the obvious as well .Reversing valve, Check valve outside,filter,filter dryers,and blower operations.I need odt,idt,and subcooling to help more. Or just add some 410 and see what happens. You must give 410 time to balance once you add a bunch. Make sure you flip yer jug over too.:cheers:

08-20-2012, 08:08 AM

JBM1000

One tiny flake of gray brazing residue from without proper nitrogen flow (even if you used it) will ruin the EEV.

08-20-2012, 04:54 PM

gravity

there is a test mode which cycles the valve open and closed. there are also sensors that could be bad. low superheat would be caused from low airflow or valve stuck wide open. also ohm your sensors and compare them to the chart

08-29-2012, 08:12 PM

ptrizzo

i would agree that it is possible low on charge with a txv you should check subcooling 410 always has to be added as a liquid its common that suction should be around 125

08-29-2012, 08:42 PM

socotech

Low charge

11-14-2012, 08:09 PM

Danimal535

Right on Gravity

11-14-2012, 08:35 PM

timebuilder

Quote:

Originally Posted by handycraftsmn

I have a Trane heat pump unit (3 ton) that the electronic txv shuts down to the point it causes the coil to ice up. It was installed 3 months ago and worked fine until 2 days ago. The board is indicating low super heat or a stuck valve. I can cycle the power and it runs great for a day and then stops cooling yet the compressor sitll runs at 50 suction and 300 head. The system is 410. Any suggestions? All pressures are good during normal operation.